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A Complicated Process: Diagnosing and Treating Anorexia Nervosa and Bulimia: Page 2 of 11

A Complicated Process: Diagnosing and Treating Anorexia Nervosa and Bulimia: Page 2 of 11

Why are these disorders difficult to diagnose? Patients with AN do not wish to be diagnosed because they do not wish to be treated. They deny the core symptomatology of their disorder and will often try to mislead their primary care provider into believing there are other medical issues causing their weight loss. Thus, it is very helpful to obtain further information from family members about the patient's behavior, if possible. Furthermore, there are problems with the DSM-IV diagnostic criteria for AN and BN (see Table 1 for an abbreviated version). The DSM-IV criteria are undergoing scrutiny because many patients suffering from eating disorders do not quite fit.

Diagnosis of Anorexia Nervosa

For AN, the criterion of weight loss would seem to be noncontroversial. However, there is no consensus as to how weight loss should be calculated. Some investigators emphasize a total weight loss from an original high weight, and others emphasize weight loss below a normal weight for age and height. Surprisingly, the degree of weight loss does not differentiate patients with AN on other characteristic clinical variables (Halmi, 1974). The psychological criteria for AN are also a problem. Through the Internet, patients with AN have learned not only diagnostic criteria but how to fool doctors both in diagnosis and in treatment. For example, they will deny the fear of gaining weight even though their behavior-such as eating very small amounts of food, fasting for long periods of time and excessive exercise-indicates they have such a fear. Thus, a positive evaluation on this criterion is often based on an inferred judgment from reportable observable behaviors.

Psychological assessments have shown that patients with AN have overwhelming maturity fears, lack of confidence in coping with life's problems and a pervasive sense of inadequacy (Kleifield et al., 1996). Staying thin is one behavior anorectic patients engage in better than anyone else, and, thus, they achieve some feeling of accomplishment by evaluating themselves in terms of their thinness. The constant preoccupation with dieting, food, weight and body image is a distraction that may well be a defense against having to face other life problems. Thus, to admit to the seriousness of their low body weight would mean acknowledgement of the necessity to change their behavior, which is an overwhelming and terrifying notion for the patient with AN.

The entire issue of amenorrhea is complicated by the fact that it is often difficult to get an accurate history of menstrual patterns. The use of birth control medication also makes evaluation of menstruation difficult. Because of this and a few examples of women who still menstruate at a low weight, there is current support for excluding the criterion of amenorrhea for diagnosis of AN.

The restricting and binge-eating/purging subtypes of AN were included in the diagnostic criteria after many studies showed both behavioral and medical differences (Halmi, 2002). Patients with the bingeing and purging subtype have a much higher association of impulsive behavior such as suicide attempts, self-mutilation, stealing and substance abuse--including alcohol abuse--compared to those with the restricting subtype. Impulsive personality disorders such as borderline personality disorder and histrionic personality disorder are far more prevalent in the bingeing and purging subtype compared to the restricting subtype. Also, the medical problems associated with bingeing and purging behavior are distinctly different from those of restrictors (Table 2).

Diagnosis of Bulimia Nervosa

Problems also exist with the diagnostic criteria for BN. The term bulimia merely means binge eating, which is a behavior that may occur on occasion in otherwise healthy people. It is difficult to define exactly how much food constitutes a binge. Obviously, a very small person eating a certain amount of food is proportionately going to be greater than a very tall person eating that same amount of food. Therefore, the definition of binge eating remains rather vague; that is, a greater than expected amount of food in a discrete period of time, such as under two hours. Earlier definitions of BN did not contain a frequency and chronicity criterion, which resulted in early population prevalence studies producing a rather high prevalence for BN, especially in vulnerable groups such as college students (Healy et al., 1985; Zuckerman et al., 1986). It then became necessary to separate those students who binged occasionally from those binge eaters who had a distinct impairment of function.

 
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